Particle emission characteristics of DPF regeneration from DPF regeneration bench and diesel engine bench measurements

Abstract

Diesel particulate filter (DPF) is an effective and state-of-the-art device to reduce the particle emission from diesel engines. Two experimental apparatuses, including a DPF regeneration bench and a diesel engine bench, were built to investigate the particle emission characteristics of DPF during the regeneration process in this work. The purpose of study is to explore the formation mechanism and influence factors of emitted particle. The DPF regeneration test bench measurements showed that some 10 nm nuclei model particles were blown out by high temperature inlet flow during DPF heating-up stage for each test regeneration temperatures. The particle concentration increased by 2–3 orders of magnitude due to this hot spot, and the mean diameter of the emitted particle rose from 10 to 20 nm to 300 nm. The diesel engine bench measurements indicated that the 10 nm nuclei model particle mainly came from the penetration of the inlet initial exhaust particles of diesel engine, and some of them originated from the blow-out of deposited soot layer during heating-up stage. The 10 nm nuclei model particle during regeneration process mainly originated from the oxidization of deposited soot layer inside DPF channels, and 100 nm aggregated model particle) were formed during this process simultaneously. The 8 g/L soot loading and the 575 °C regeneration temperature led to large total amount of emitted particles in the downstream of the DPF. Both 4 g/L and 8 g/L DPFs had moderate regeneration efficiencies and relative low total particle emission, when the regeneration temperature was 550 °C.